A wireless communication system may include, for example, a Mobile Subscriber Station (MSS) able to communicate with a Base Station (BS). The system may utilize a Hybrid Automatic Repeat Request (HARQ) scheme in order to improve link utilization via time diversity. For example, in a downlink, the BS transmits to the MSS an encoded HARQ packet, and waits for a response from the MSS.
If the MSS is able to correctly decode the HARQ packet, the MSS transmits to the BS a single-bit Acknowledgement (ACK). Once the BS receives the single-bit ACK the BS proceeds to transmit a subsequent packet queued for transmission.
In contrast, if the MSS fails to correctly decode the HARQ packet, the MSS transmits to the BS a single-bit Negative Acknowledgement (NACK). The MSS may store the incorrectly received packet, for further re-processing with subsequent re-transmission packet(s). Once the BS receives the single-bit NACK, the BS transmits to the MSS another encoded HARQ packet. The BS may continue to re-transmit the encoded HARQ packet until the BS receives from the MSS a single-bit ACK, or until a maximum allowed number of retransmissions is reached.
The HARQ mechanism may further be utilized in uplinks. For example, the MSS transmits to the BS an encoded HARQ packet, and the BS transmits to the MS a single-bit ACK or a single-bit NACK.